Oral malodor, plaque, gingivitis, periodontal disease, and discoloration of the teeth, are all undesirable conditions that affect many people. First malodor of the oral cavity also known as halitosis or oral malodor has been broadly estimated to afflict 20 to 90 million individuals in the U.S. It is generally believed that the presence of anaerobic bacteria, especially gram-negative anaerobic bacteria, in the mouth contributes to this condition. Other oral conditions caused by microorganisms include periodontal disease, tooth decay, inflammation and the like.
Periodontal disease is a major cause of tooth loss in adults, and can manifest itself in people as young as age 12. Periodontal disease affects the periodontum, which is the investing and supporting tissues surrounding a tooth (i.e., the periodontal ligament, the gingiva, and the alveolar bone). Gingivitis and periodontatitis are disorders of the gingiva and the deeper periodontal tissues, respectively. Periodontal disease is generally associated with the accumulation of plaque on the teeth. The teeth are coated with a salivary proteinaceous material (pellicle) and thereafter streptococci adhere to this coating. Gingivitis occurs from the dental plaque, and periodontatitis is caused by the infection spreading to the periodontal pocket or space between the gingival and the tooth root.
Many of the current oral care compositions including toothpastes, mouthwashes, rinses and tooth gels are formulated to clean the oral cavity and kill pathogenic microbes. Such oral care compositions are typically formulated with one or more antimicrobial agents to suppress microorganisms that contribute both to the initiation and progression of oral malodor, periodontal disease and other undesirable oral conditions. One such antimicrobial agent is hinokitiol, or beta-thujaplicin. Hinokitiol has been used as an antiseptic that exhibits low stimulative or irritative effects on the skin of the human body. However, hinokitiol is not very water-soluble, and is not sufficiently stable under all conditions in which its use is desirable. Compositions containing hinokitiol lose antimicrobial efficacy when exposed to air and light, and form hinokitiol precipitates on the walls of the container, thus further reducing the efficacy and usefulness of such compositions.
There is a need for developing efficacious oral care compositions such as mouthwashes or rinses, containing antimicrobial agents having favorable antimicrobial kinetics while exhibiting suitable chemical stability and solubility for effective delivery of the agents to the oral cavity. There is a need for compositions with enhanced antimicrobial kinetics to provide effective prevention or treatment of diseases and conditions of the oral cavity by killing pathogenic oral microorganisms responsible for plaque, gingivitis and other undesirable oral conditions.